NK cells, key cells in immune responses,563 are affected by NETs, as demonstrated by an in vitro study showing that NETs can inhibit NK cell migration and motility.201 In a TME abundant in NETs, the therapeutic efficacy of NK cells is impaired,285 possibly due to MMP9 in NETs contributing to NK cell dysfunction and tumor invasion.564 Inhibition of NETs in a murine model of HCC enhanced anti-tumor immunity mediated by NK cells. The gene discussed is MMP9; the disease is neoplasm.